1. Field of the Invention
The present invention relates to: a communication method employing a repeating apparatus that is capable of relaying communication among a plurality of apparatuses capable of performing half duplex communication and that performs multi-address calling of data received from one apparatus having acquired transmission right, to the other apparatuses having been grouped with said one apparatus; a communication system employing such communication method; and a connection apparatus employed in such communication system. In particular, the present invention relates to a communication method, a communication system, and a connection apparatus applicable to a PoC (Push-to-Talk over Cellular) service in which the technique of IP (Internet Protocol) telephone is utilized in a manner similar to transceivers so that a packet containing voice data is transmitted to a plurality of apparatuses by multi-address calling.
2. Description of Related Art
Recently, the use of real-time applications such as VoIP (Voice over Internet Protocol), VoPN (Voice over Packet Network), and streaming or the like is increasing in which audio and video data are transmitted and received between apparatuses via a communication network such as an IP (Internet Protocol) network. Thus, IP telephone serving as an example is spreading rapidly. In the IP telephone, packeted voice data is transmitted and received via an IP network so that telephone call is realized between an apparatus on the packet transmitting side and an apparatus on the packet receiving side.
Further, attention is focused on a PoC (Push-to-Talk over Cellular) service in which the technique of IP (Internet Protocol) telephone is utilized in a manner similar to transceivers so that a packet containing voice data is transmitted to a plurality of apparatuses by multi-address calling. A feature of the PoC service is that half duplex communication is adopted in which one apparatus among a plurality of apparatuses acquires transmission right for transmitting voice data and then this one apparatus having acquired the transmission right performs multi-address calling of voice data to a plurality of the other apparatuses. This permits simultaneous communication among three or more apparatuses. Here, at the time of transmission of the voice data, which apparatus (user) has presently the transmission right is notified to each apparatus. This allows all members to understand who is providing the speech presently outputted on the basis of the voice data (see, for example, Japanese Patent Application Laid-Open No. 2005-102033).
As such, in a system that realizes one-to-a-plurality conversation by means of multi-address calling of voice data from one apparatus having acquired transmission right to a plurality of the other apparatuses similarly in the PoC service, time, effort, and cost are reduced that is necessary for transmitting the same contents to each person. Further, even in a case where a speech is intrinsically directed to a specific person, when a speaking person having acquired transmission right transmits the contents also to the other persons by multi-address calling, the information is shared among all the members including the persons other than the intrinsic target person of the speech. This is another advantage.
Nevertheless, although dedicated terminal devices are necessary for the use of the PoC service, there is a problem that dedicated terminal devices are not spreading widely at present. In order to use the dedicated terminals, corresponding financial burden such as purchase expense obviously arises. This causes a difficulty in the use of the PoC service, hence prevents increase in the name recognition of the PoC service itself and its advantage, and thereby causes a problem that the PoC service does not spread widely.